Normally, we use carbon steel like

SK45: HRC15-20

60#: HRC28-32

70# HRC36-39,HRC39-42


Carbon steel, also called plain-carbon steel, is a metal alloy, a combination of two elements, iron andcarbon, where other elements are present in quantities too small to affect the properties. The only other alloying elements allowed in plain-carbon steel are: manganese (1.65% max), silicon (0.60% max), and copper(0.60% max). Steel with a low carbon content has the same properties as iron, soft but easily formed. As carbon content rises the metal becomes harder and stronger but less ductile and more difficult to weld. Higher carbon content lowers steel's melting point and its temperature resistance in general.